Linux Device Drivers, Second Edition

Version Numbering

Before digging into programming, we’d like to comment on the version numbering scheme used in Linux and which versions are covered by this book.

First of all, note that every software package used in a Linux system has its own release number, and there are often interdependencies across them: you need a particular version of one package to run a particular version of another package. The creators of Linux distributions usually handle the messy problem of matching packages, and the user who installs from a prepackaged distribution doesn’t need to deal with version numbers. Those who replace and upgrade system software, on the other hand, are on their own. Fortunately, almost all modern distributions support the upgrade of single packages by checking interpackage dependencies; the distribution’s package manager generally will not allow an upgrade until the dependencies are satisfied.

To run the examples we introduce during the discussion, you won’t need particular versions of any tool but the kernel; any recent Linux distribution can be used to run our examples. We won’t detail specific requirements, because the file Documentation/Changes in your kernel sources is the best source of such information if you experience any problem.

As far as the kernel is concerned, the even-numbered kernel versions (i.e., 2.2.x and 2.4.x) are the stable ones that are intended for general distribution. The odd versions (such as 2.3.x), on the contrary, are development ...